The invention relates to a method for detecting the foreground or background vector near a discontinuity in a vector field.
In several technical fields of imaging technics it is required to know which velocity around an object edge or velocity discontinuity is the foreground velocity and which is the background velocity.
The invention has as an object to provide a method for detecting said velocities.
According to a first strategy of the invention said object is achieved in that it is determined whether covering or uncovering situation exists, that at the position {right arrow over (x)}1 of the discontinuity
a first position {right arrow over (x)}a in the previous (covering) or next (uncovering) vector field is calculated by shifting {right arrow over (x)}1 over the first vector at one side of the discontinuity,
a second position {right arrow over (x)}b in the previous (covering) or next (uncovering) vector field is calculated by shifting {right arrow over (x)}1 over the second vector at the other side of the discontinuity
and a third intermediate position between {right arrow over (x)}a and {right arrow over (x)}b is calculated, in which the vector fetched with v{right arrow over (a)}v at the third position in the previous (covering) or next (uncovering) vector field is the background vector.
According to a second strategy of the invention said object is achieved in that it is determined whether covering or uncovering situation exists, and that two positions on either side of the discontinuity are projected to the previous (uncovering) or next (covering) vector field, in which a background velocity is identified as a velocity which crosses the velocity discontinuity and projects to a foreground velocity in the previous picture, whereas a foreground velocity projects to itself.
According to the third strategy of the invention said object is achieved in that it is determined whether covering or uncovering situation exists, that the discontinuity is projected to the previous vector field in the covering situation and to the future vector field in the uncovering situation, near discontinuities it is tested whether the mentioned edge has moved over the first vector on one side of the discontinuity, or over the second vector on the other side of the discontinuity, and that in case the discontinuity moves with the first (second) vector, the second (first) vector is the background vector v{right arrow over (B)}G.
The invention further relates to a foreground/background detector having corresponding features.
Further elaborations of the invention are specified in the dependent subclaims.
The invention will be described in more detail with reference to the attached drawings.